The PHP Lifecycle
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Summary
• B/S(HTTP Request Cycle)
• Apache Life Cycle
• Apache Parse Request Cycle
• PHP Life Cycle
• Cooperating with Apache
• PHP Parse/Execute Process
• Now We Can…
Linux/Unix + Apache 1.3x + PHP 5.x

B/S
1. Client Request
2. Server Parse Requst and Send Response
3. Client interpret Responded Text/HTML/Json etc…

Apache Life Cycle

Apache Parse Request Cycle

PHP Life Cycle
• In command line mode(CLI)

PHP Life Cycle con’t
• PHP_MODULE_ENTRY(php_mysql.c 215 行 )

PHP Life Cycle con’t
• PHP_MINIT_FUNCTION(php_mysql.c 378 行 )

PHP Life Cycle con’t
• PHP_RINIT_FUNCTION(php_mysql.c 473 行 )

PHP Life Cycle con’t
• PHP_SHUTDOWNS(php_mysql.c 403 行 )

PHP Life Cycle con’t
• In DSO mode
– Single process

PHP Life Cycle con’t
• In DSO mode
– Multiprocess

PHP Life Cycle con’t
• In CGI mode
– Multithreaded

Cooperation
• Apache 1.3x + PHP 5.x in DSO mode
• Dynamic Shared Objects (DSO)
– mod_dso
• src/modules/standard/mod_so.c 347 行

Cooperation con’t
• Php Module 注册 Handler
– mod_php5.c 963 行

Cooperation con’t
• Php Module 注册 Handler
– mod_php5.c 987 行

Cooperation con’t
• http.conf

PHP Parse/Execute Process

PHP Parse/Execute Process con’t
• Scan(lex)
– Zend/zend_language_scanner.c 3047 行
ZEND_API zend_op_array *compile_file(zend_file_handle *file_handle, int type TSRMLS_DC){
retval = op_array;
….
return retval;}
– Zend/zend_language_scanner.l
T_OPEN_TAG: '<?php '
=
<?php T_LNUMBER: '1'
$sum = 1 + 2; +
echo “1+2=“.$sum; T_LNUMBER: '2'
?> T_ECHO: 'echo''
T_CONSTANT_ENCAPSED_STRI
NG: ''1+2=''.
T_CLOSE_TAG: '?>'

PHP Parse/Execute Process con’t
• Parse/Complie(yacc)
– zend_language_parser.y
T_OPEN_TAG: '<?php '
= Opcode Op1 Op2 Result
T_LNUMBER: '1' ADD 1 2 $tmp0
+ ASSIGN $cv0(sum) $tmp0 $var1
T_LNUMBER: '2' CONCAT '1+2=' $cv0(sum) $tmp2
T_ECHO: 'echo'' ECHO $tmp2
T_CONSTANT_ENCAPSED_STRI RETURN 1
NG: ''1+2=''.
T_CLOSE_TAG: '?>'

PHP Parse/Execute Process con’t
• Execute
– Zend/zend_execute.c
void (*zend_execute) (zend_op_array *op_array TSRMLS_DC);
• Zend_op_array
– Zend/zend_compile.h
struct zend_op{
opcode_handler_t handler;
znoderesult;
znodeop1;
znodeop2;
ulongextended_value;
uintlineno;
zend_ucharopcode;
};

PHP Parse/Execute Process con’t
• Execute
– Zend/zend_opcode.c 428 行

A sample
• Clien Request

A sample
• http_main.c 8053
– main() call ap_main
• ap_main => REALMAIN
– REALMAIN(argc, argv)
– http_main.c
• child_main
– Call child_sub_main 6134
• chile_sub_main
– loop worker
– call ap_process_request(r) on request
• http_reqeust.c 1308
• ap_process_request
– call process_request_internal
• process_request_internal
– call ap_invoke_handler
Application/x-httpd-php -> send_parsed_php

A sample
• Server Pares
– URI
• Filename -> /test/index.php
– User Auth
– …
– MIME type Check
• application/x-httpd-http
– Call handler
• send_parsed_php(request_rec *)
• Zend_execute_script(…..request_rec->filename);

A sample
• Zend/zend.c 1073 行

A sample
• Index.php
<?php
echo 2+3;
?>

A sample
• Zend_language_scanner.l 362 行
• Zend_language_parse.c 62 行

A sample
• Parser
– Zend_language_parse.y
– Zend_compile.c 258 行

A sample
• Opcodes

A sample
• Zend_execute zend.c 594 行
– Zend_execute => execute
• execute zend_vm_execute.h 34 行
ZEND_API void execute(zend_op_array *op_array TSRMLS_DC)
• Generate Output
• Return to Apache Server process
• Server send Responds Text to Client.

Now We Can….
• 1, 服务器的 Access log 没有任何输出
• 2, 隐藏 PHP 文件类型
• 3, PHP 出错的阶段
• 4, 编写 PHP 扩展
• 5, …

Documents
• 《 Apache Server 源代码分析》
• 《 Writing Apache Modules with Perl and C 》
• 《 Extending and Embedding PHP 》
• 《 PHP 手册》：“ Zend API ：深入 PHP 内核”
• http://blog.csdn.net/laruence

谢谢大家！